This invention relates to dentifrice compositions and, more particularly, to antiseptic dentifrice compositions wherein hydrogen peroxide and ammonia are produced in situ during oral application of the dentifrice.
Dentifrices, in powder, paste, cream and liquid forms, are used for both cosmetic and therapeutic purposes. Consistent with these purposes, dentifrices are formulated to contain active ingredients such as cleansing and polishing materials, as well as various antibacterial and anticaries agents for use as aids in the prevention of tooth decay.
It is generally understood in the dental art that certain kinds of tooth decay are initiated by acid etching of the tooth enamel with the source of the acid being a metabolite resulting from bacterial and enzymatic action on food particles in the oral cavity. It is hypothesized that plaque--which is a soft accumulation on the tooth surfaces consisting of an organized structure of microorganisms, proteinaceous and carbohydrate substances, epithelial cells, and food debris--is a contributory factor in the development of various pathological conditions of the teeth and soft tissue of the oral cavity. It has been suggested that the saccharolytic organisms of the oral cavity, which are associates with the plaque, cause decalcification beneath the plaque matrix through metobolic activity which results in the accumulation and localized concentration of organic acids. The etching and decalcification of the enamel may continue until the pulp chamber of the tooth is reached.
A wide variety of materials have been considered for use as decay-preventative agents in dentifrice compositions. Some of the substances which have been so considered include para-aminobenzoic acid, a combination of urea and urease to produce ammonia during oral application of the dentifrice, chlorophyll, perflourinated long chain organic compounds, complex iodine, penicillin, benzohydroxamic acid, and glucose oxidase to produce hydrogen peroxide during oral application of the dentifrice.
U.S. Pat. No. 2,526,614 (Butterfield, 1950) discloses the incorporation into a dentifrice of an enzyme system comprising urea and urease which produces ammonia in the presence of moisture that is encountered during oral application of the dentifrice. The patentee reports that the action of the ammonia together with residual urea is bacterocidal to acidogenic organisms and antienzymatic to the production of lactic acid by such organisms. In addition, it is pointed out that the action of ammonia produced from this enzyme system dissolves mucin plaques.
U.S. Pat. No. 3,427,380 (Kirkland, 1969) discloses that oral organisms produce a capsular material which is a factor in holding plaque together and allowing its further growth and that the oral application of a dentifrice containing para-aminobenzoic acid inhibits capsule formation by such organisms and thereby retards the development of dental plaque without inhibiting the growth of these organisms.
U.S. Pat. No. 3,137,634 (Schiraldi, 1964) discloses that the oral application of a dentifrice composition containing, for example, potassium copper chlorophyllin, dicalcium phosphate dihydrate, and tetrasodium pyrophosphate is useful in the treatment of gum diseases such as periodontal disorders like gingivitis, pyorrhea and trench mouth and, in addition, reduces undesirable breath odors.
U.S. Pat. No. 3,227,618 (Dunellen, 1966) in the background portion of the specification, recites that it has been disclosed that treatment of tooth enamel with a mixture of stannous flouride, hydrogen peroxide and insoluble sodium metaphosphate increases the enamel hardness as described in The Journal of the American Dental Association, May, 1950, Vol. 40, pg. 513-519.
Merck Index, 9th Edition, 1976, at page 633, discloses that hydrogen peroxide solution 3% contains 2.5-3.5 wt. % of hydrogen peroxide which is equivalent to 8-12 volumes of oxygen, and that this solution is a topical anti-infective which is useful in pharmaceutical preparations such as mouthwashes, dentifrices, and sanitary lotions.
U.S. Pat. No. 4,150,133 (Hoogendorn et al, 1979) discloses an enzymatic dentifrice containing glucose oxidase which acts on glucose present in saliva and tooth plaque to produce hydrogen peroxide.
Hydrogen peroxide is a fast acting, broad spectrum oral antiseptic. Unlike other anitbacterials which continue into the digestive tract, hydrogen peroxide has the advantage of quickly breaking down into oxygen and water in the oral cavity. Hydrogen peroxide is also converted into oxygen and water in the oral cavity by the enzymatic action of catalase which is present in saliva.
Previous attempts to incorporate hydrogen peroxide into dentifrices such as toothpaste have met with limited success, due to the instability of hydrogen peroxide in the packaged product.